G. Washington A340 6c Chocolate Not Red-Orange

I have a stamp of G. Washington A140 6 cents that is not red-orange as described in the Scott Catalogue (SC 336 or 362 or 379) but chocolate color. I cannot find any other issue of this stamp 6c model for this different color. It is there somewhere!!


sorry for the bad obliteration mark on Washington face!.

Your picture is horrendous. That being said, use the forum search engine and look for "changeling". You will find hundreds of threads about stamps that have changed color due to environmental damage. Oranges are the worst offenders. Amongst other things they tend to oxidize. The threads will go into detail.

Hi, a while ago I presented mine here with the same question. I was told that orange could change into brown, depending on different external factors.

It's called lead poisoning.
The ink(s) used for the stamps contain lead and in the presence of sulfur turn the lead into PbS (lead sulfide) which is a black substance. Your stamp will end up as black over time. Usually yellows and reds are the problematic colors.

On used stamps, you can soak them in a hydrogen peroxide (H2O2) solution and the following reaction takes place:
PbS + 4 H2O2 -> PbSO4 + 4 H2O
PbSO4 is lead sulfate, a colorless substance.

You can do that once or twice because hydrogen peroxide also attacks the paper structure and weakens it. If you have stamps that show browning, you should remove them as they will infect the good stamps over time.